Nursing Elites

1. What is hydroxyapatite?

• A. A mixture of minerals such as calcium and phosphorus that strengthen the collagen matrix of bone.
• B. The structural unit of a bone that runs the length of the bone.
• C. The covering of bones at the point of articulation to prevent grinding.
• D. The lightest portion of a long bone and concentrated at the ends.

Correct answer: A

Rationale: Hydroxyapatite is a mineral compound composed of calcium and phosphorus that plays a crucial role in strengthening the collagen matrix of bones, contributing to their structural integrity and hardness. It is a key component of bone tissue and provides the mineralization necessary for bone strength and density. Choice B is incorrect because the structural unit of a bone is the osteon or Haversian system, not hydroxyapatite. Choice C is incorrect as it describes cartilage, not hydroxyapatite. Choice D is incorrect as it refers to the epiphysis, which is not synonymous with hydroxyapatite.

2. Which of these is NOT a function of the large intestine?

• A. Absorbing water and electrolytes
• B. Producing vitamins
• C. Breaking down fiber
• D. Eliminating waste products

Correct answer: B

Rationale: A) Absorbing water and electrolytes: The large intestine plays a crucial role in absorbing water and electrolytes from the indigestible food matter that passes through it. This helps in maintaining the body's fluid balance and preventing dehydration. B) Producing vitamins: While the large intestine contains bacteria that can produce some vitamins like vitamin K and certain B vitamins, the primary site for vitamin production is the small intestine and other organs like the liver. Therefore, producing vitamins is not a primary function of the large intestine. C) Breaking down fiber: The large intestine is responsible for breaking down fiber that was not digested in the small intestine. The bacteria in the large intestine ferment fiber, producing short-chain fatty acids that can be used as an energy source by the body. D) Eliminating waste products: One of the main functions of the large intestine is to eliminate waste products, including indigestible food matter, dead cells, and bacteria, from the body in the form of feces. Therefore, the correct answer is B, as producing vitamins is not a primary function of the large intestine.

3. Which of the following is an example of a salt?

• A. Sodium hydroxide (NaOH)
• B. Hydrochloric acid (HCl)
• C. Sodium chloride (NaCl)
• D. Sulfuric acid (H₂SO₄)

Correct answer: C

Rationale: Sodium chloride (NaCl) is an example of a salt. Salts are ionic compounds formed by the reaction of an acid with a base. In this case, sodium chloride is formed by the reaction of sodium hydroxide (a base) with hydrochloric acid (an acid). Sodium hydroxide (NaOH), hydrochloric acid (HCl), and sulfuric acid (H₂SO₄) are not salts because they are not formed by the neutralization reaction of an acid and a base, which is a characteristic of salts.

4. What is the half-life of a radioactive isotope, and how does it relate to its decay rate?

• A. The time it takes for half of the initial sample to decay.
• B. The time it takes for all of the sample to decay.
• C. The rate at which new isotopes are created.
• D. The energy released during decay.

Correct answer: A

Rationale: The half-life of a radioactive isotope is the time it takes for half of the initial sample to decay. After one half-life, half of the radioactive atoms have decayed. The decay rate, however, refers to the rate at which radioactive atoms decay, which is not directly related to the half-life. Choice B is incorrect because it does not correctly define the half-life. Choice C is incorrect as it refers to the creation of new isotopes, not the decay process. Choice D is incorrect as it describes the energy released during decay, which is not the same as the concept of half-life.

5. According to Newton's third law of motion, if you push against a wall with a certain force, the wall will push back with:

• A. A smaller force
• B. An equal force
• C. A greater force
• D. No force at all

Correct answer: B

Rationale: According to Newton's third law of motion, for every action, there is an equal and opposite reaction. When you push against a wall with a certain force, the wall will push back on you with an equal force in the opposite direction. Choice A is incorrect because the wall exerts an equal force back. Choice C is incorrect as it suggests a greater force, which goes against Newton's third law. Choice D is incorrect as the wall does exert a force back in response to your push.

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